HOW TO MAKE COLD PROCESS HANDMADE SOAP

Recipe ideas at the bottom of the page

Equipment needed

(no aluminium)

Scales with 1 gram increments

Stainless steel / glass / pyrex bowl and saucepan (heatproof)

Measuring cup for sodium hydroxide (Caustic Soda)

Measuring spoons, cups or droppers for essential oils

2 thermometers (1 for lye solution, 1 for base oils)

Moulds

Pestle and mortar (for crushing botanicals)

Slotted stainless steel or plastic spoon

Oil spray (optional for plastic moulds) or freezer film (for wooden moulds)

Goggles, gloves, mask, apron

Old towels

Basic Ingredients (by weight)

1kg oil of your choice

Caustic soda (see guide below - multiply the weight of the chosen oil by the saponification value to find the weight of the caustic soda required eg 1000 grams olive oil - 0.134 x 1000grams = 134 grams caustic soda.  Allow around 5% less so that your soap is more moisturising.)

375 grams water

Essential Oil  2-3%

Botanicals  (eg lavender buds, herbs, spices etc)

 

Saponification values of common soap oils

Avocado - 0.133

Beeswax  - 0.069

Borage - 0.136

Castor  - 0.128

Cocoa Butter - 0.137

Coconut  - 0.190

Jojoba  - 0.069

Olive  - 0.134

Palm  - 0.141

Shea Butter - 0.128

Sunflower - 0.134

Sweet Almond - 0.136

 

Basic Cold Processed Soap Method

  1. Gather all of the equipment that you require. It is a good idea to place newspaper down on the bench if you are working in your kitchen. Weigh the base oils in a saucepan. Weigh the water and place into a heatproof bowl. Weigh your sodium hydroxide. Prepare any botanicals that you will be adding and measure out your essential / fragrance oils. Ensure that all of your measurements are accurate. Prepare your moulds.
  2. I always start to melt the base oils before adding the sodium hydroxide to the water as the oils that I use take longer to heat than the lye (sodium hydroxide and water solution)  takes to cool. It is also easier to control the temperature of the oils as the saucepan can be removed or replaced on the stove.
  3. Put on your goggles, apron, facemask and gloves. Slowly pour the sodium hydroxide into the water and mix until dissolved. NEVER POUR WATER INTO THE SODIUM HYDROXIDE.
  4. The base oils and sodium hydroxide and water mixture (lye) need to be at certain temperatures before mixing together. I heat my base oils to around 50-60`C and the lye solution to around 50-60`C. Once the oils and lye have reached these temperatures carefully pour the lye solution into the oil.
  5. Stir the mixture until it traces. Trace is when it looks a bit like custard or you can pile up a small amount on top of the mixture and it stays at least for a few seconds. If you have the time you can stir with a spoon which can take a few hours or even a day to trace or if you don't have that sort of patience (like me!) you can use a stab mixer and it can take just a few minutes.

My first batch I stirred with a spoon for around 2 ½ hours and then feeling a little frustrated (and tired..) a grabbed out my stab mixer and trace occurred within about 1 minute! Now I always use the stab mixer from the start and it only takes about 2-3 minutes for a 1 ½ kg batch and a couple of minutes longer for a double batch. If it takes a while to trace make sure you rest the stab mixer every 30 seconds so the motor doesn't burn out.

  1. Now is the time to stir in your botanicals and essential oils.
  2. Mix thoroughly and pour into your mould. Wrap the mould in old towels to help insulate and regulate the temperature. This is needed for the soap to gel.
  3. Soap will be ready to remove from mould in around 24 - 48 hours. Soap will be quite soft but will harden over the next few weeks. I cut my soap as soon as I have taken it out of the mould but some people prefer to wait until it hardens a little. Soap needs to be left to cure and harden for at least 4 weeks. It will then be ready to use.

 

Recipe Ideas

(Always double check that the sodium hydroxide calculation is correct)

 

Recipe 1

500 grams Pomace Olive Oil

250 grams Palm Oil

250 grams Coconut Oil

145 grams Sodium Hydroxide

375 grams Water

25ml Lavender Pure Essential Oil

Lavender Buds to sprinkle on top

 

Recipe 2

400 grams Coconut Oil

300 grams Pomace Olive Oil

250 grams Sweet Almond Oil

50 grams Shea Butter

150 grams Sodium Hydroxide

375 grams Water

25mls Rose Geranium Pure Essential Oil

3 teaspoons Red Clay

Rose Petals to sprinkle on top